Fix up tests for change in all.equal behavior

R-devel (will be R 3.2.0) has a change in behavior of all.equal for environments.
This change fixes the tests for this new behavior.
Update README.md

I see that the `lazy` package name has changed to `lazyeval`
Merge pull request #270 from ijlyttle/patch-2

Update README.md
Bump dplyr version dependency
Remove `:=`
Update test specs
Update NEWS
new histogram stuff based on center/width/boundary
right = TRUE -> closed = "right"
Revert extraneous changes and style fixes
Simplify compute_bin code
Revamp compute_bin tests
Re-document